1. Field of the Invention
The present invention relates to an apparatus for recording information concerning photographic exposure by a camera.
2. Related Background Art
In general, a silver salt color developing process for producing a color print from a color negative film after exposure is composed of two major steps: namely, development of an image on the color negative film and printing. These two steps are executed under various controls in order to reproduce the color tone and contrast of the photographing object with high fidelity. Unfortunately, however, it is often experienced that the resultant color copy gives an impression which is entirely different from that of the photographing object imparted to the photographer at the time of the photographing operation.
In particular, in an automatic print system in which color prints are produced from many negative films, it is essential that color prints of high quality be produced in a short time at a high efficiency. Unfortunately, known automatic printing systems often produce color prints which are quite different from the object both in color tone and contrast.
Known daylight-type color negative printing systems are designed such that the color tone of the object can be reproduced with the highest level of fidelity when the exposure is done under illumination of 5500K in terms of the color temperature. Therefore, when the exposure is to be conducted under different conditions of illumination, a color temperature conversion filter is disposed in the path of light between the object and the film so as to convert the color temperature to 5500K or, alternatively, a color correction is performed in the course of the printing.
Another problem is that the reproducible allowable exposure ranges of a color negative film and a color photosensitive paper, i.e., density range with respect to the exposure range, are undesirably restricted when the exposure is made with a large exposure light quantity or a small exposure light quantity. For instance, when a person is photographed in bright and clear condition, the resultant color print produced by known automatic print systems exhibits a too high contrast with inferior delineation of texture of human skin, if the printing is conducted with an inadequate quantity of light.
In order to optimize the color tone and contrast of a color print, it is a common practice to measure the color tone and density of individual color negative films prior to the printing and to determine the printing light quantity and amount of color correction in accordance with the result of the measurement. In recent years, automatic printing systems of this type, generally referred to as separate measurement type, are becoming popular. More specifically, in this type of automatic printing system, each frame of each color negative film is divided into a plurality of pixels and the color tone and the density of the individual pixels are measured and statistically analyzed thereby determining the quantity of the printing light and the amount of correction of the color. The color tone and the contrast of a color print, however, are not always optimum even when the print is produced by this type of automatic printing system. Namely, the color tone and the contrast are sometimes not corrected satisfactorily, particularly when the photos are taken in a back light or in the dim light of a sunset, as well as in a shadow of a tree, in the vicinity of a window, at seashore, looking up at a mountain covered with snow, in the light of a tungsten lamp, and so forth.
To reproduce the color photograph with good color tone and contrast, therefore, it is a common measure that a skilled person in the developing factory visually checks the color negative film in a frame-by-frame fashion and corrects the printing light quantity and the amount of color correction given by the measuring device in accordance with the result of the visual check. Alternatively, the person skilled in the art visually checks the color print as produced by the automatic printing system and, in case of any inferior print, conducts the printing again under revised printing conditions.
Under these circumstances, techniques have been proposed for improving reproducibility of the color tone and contrast in color printing.
For instance, U.S. Pat. No. 4,574,319 discloses an art in which a color temperature meter is incorporated in a photographing camera so that the color temperature information with the object is recorded, and the printing is conducted by making use of this color temperature so as to provide a color print of a high quality.
On the other hand, Japanese Patent Unexamined Publication No. 59-162532 discloses an art in which information as to whether an electronic flash was used is recorded in a memory provided in the camera and this information is fed back to the printing process, thereby improving the quality of the color print.
These proposals, however, are disadvantageous in that they require a color temperature measuring device to be incorporated in a camera, with the result that the production cost of the camera is raised undesirably.
Another problem is that the color temperature information alone cannot provide sufficient information for enabling the determination of the color correction amount or the printing light quantity in a developing factory.
Thus, the proposed systems cannot enable the reproduction of the color tone which the photographer wishes to reproduce because the information pertains only to the color temperature or whether an electronic flash was used or not.
The automatic printing system, on the other hand, inherently has a problem in that the photographing effect which the photographer intended to obtain at the time of photographing cannot be obtained in the produced color print.
For instance, photographers selectively use color temperature conversion filters. A photographer may attempt to neglect the use of a color temperature conversion filter in order to put an emphasis on the blue tone when photographing at a comparatively high color temperature as in the case of an exposure in a rainy or cloudy condition. Similarly, the photographer may attempt to put an emphasis on red color tone to realize a scene in the sunset where the color temperature is low, by using a color temperature conversion filter which serves to intentionally change the color temperature away from the standard color temperature of 5500K. If the enlarging and printing are executed with color temperature correction conducted in accordance with the color temperature information recorded in the camera, the color print will be obtained as if the photograph was taken in a bright and clear condition under daylight, thus inconveniently failing to reproduce the specific photographing effect which the photographer intended to reproduce.
Furthermore, a photometric device on a camera produces a signal representative of the exposure light quantity optimum for the film, on an assumption that the object to be photographed has a reflectivity of about 18% corresponding to a gray color. Therefore, if the exposure is performed in accordance with the output from the photometric device, an object having a high reflectivity such as a white wall or an object having a low reflectivity such as a black wall is recorded in a gray color on the film. In order to obviate this problem, the photographer corrects the exposure condition such as to reduce the light quantity as compared with the exposure light quantity output from the photometric device when he wishes to reproduce a black object in a black color. Conversely, when the photographer wishes to obtain a white print image of a white object, he corrects the exposure condition such that the exposure is conducted with an exposure light quantity greater than the value indicated by the photometric device. Cameras have been known which are operable both in an automatic exposure mode in which the shutter speed (time value) and the aperture value are automatically controlled in accordance with the output from a photometric device and a manual mode in which the photographer can manually set the exposure condition. When the camera is used in the automatic exposure mode, the above-mentioned correction of the exposure condition is effected by manually operating an exposure condition correction device on the camera or, alternatively, the camera is switched to manual exposure mode and the photographer manually sets the time value and the aperture value such that an exposure light quantity greater or smaller than that indicated by the photometric device is obtained.
In an enlarging process in which the image on a color negative film is printed on a photosensitive paper in an enlarged size, the light quantity of the printing exposure light quantity is determined in accordance with the result of an automatic reading of the density of the negative film. Therefore, even if the photographing is executed through a photographing exposure control such as to increase the light quantity for the purpose of producing a white print image of a white object, the printing exposure light quantity is automatically controlled to a smaller value because of the large density of the image on the negative film, with the result that the image of a white object is reproduced in a gray color. Similarly, even if the photographing exposure has been executed with an exposure correction such as to reduce the exposure light quantity with a view to obtain a black print image of a black object, an automatic printing control is undesirably effected to decrease the printing exposure light quantity because in this case the density of the image on the negative film is low, so that the image of the black object is printed in a gray color.
Still another problem is encountered in regard to the use of an electronic flash device. In general, an electronic flash device is used not only in photographing in the night time or in a house and the like but also in outdoor photographing in the daylight, practically when the object is illuminated by a back light as in the case of an object in shadows of trees or an object near a window. When such an object is photographed, the object is illuminated both by the natural light and the flash light, so that information showing that a flash device was used or information of the color temperature of the object solely may fail to provide an index for an optimum color correction.